1. Field of the Invention
This invention relates to lasers, and more particularly concerns design of an improved waveguide laser having multiple cavities.
2. Description of Related Art
An important goal in the development and design of working lasers is achievement of a small size, high power and lightweight laser system. Compact, high power lasers have many possible fields of application, including communication, manufacturing, and medicine. Particularly in the fields of medicine and communication, light, small and high power instruments are desired.
The conventional gas laser, although producing a suitably high power output, fails to lend itself to sufficiently compact and lightweight designs for many applications. Waveguide gas lasers have been developed in an attempt to overcome existing problems of prior gas lasers. The waveguide gas laser incorporates a resonator in which radiation is transmitted in part by guided wave propagation, which is in contrast to the conventional laser where feedback and resonator modes are established by normal free space propagation. Advantages of most waveguide laser systems as compared to conventional lasers include reduced laser size, use of flat, instead of curved mirrors, smaller transverse dimensions, high laser gain and pressure broadened lasers. The waveguide laser has potential for compact, low power lasers otherwise not possible. Other advantages include high pressure operation resulting in increased frequency tunability in lasers such as carbon dioxide systems, efficient matching between the optical resonating and laser excitation means, and excellent mode control through the unique properties of waveguide laser resonators.
Examples of waveguide gas lasers are disclosed in the following U.S. patents: U.S. Pat. Nos. 4,577,323 to Newmann et al, 4,103,255 to Schlossberg, 4,464,758 to Chenausky et al, 4,429,398 to Chenausky et al, 4,169,251 to Laakmann, and 4,129,836 to Papayoanou.
Various techniques for constructing waveguide cavities of prior art waveguide gas lasers exhibit problems in the scaling of cavities and the coupling of the exciting energy to the cavities. Where the waveguides are formed in a plurality of ceramic blocks, solder or epoxy has been used for securing and sealing the blocks to one another. However, such techniques employ materials that may give off gases which contaminate the lasing medium and may lack desired temperature stability and sealing characteristics. Significant problems exist in providing exciting electrodes. Direct current excitation of such waveguide gas lasers has required a relatively large DC excitation between a pair of electrodes positioned near respective ends of a relatively long laser waveguide cavity. Such an arrangement requires large voltages, power supplies and circuitry capable of handling such voltages. To avoid problems with direct current excitation, radio frequency excitation has been suggested, but again introducing the difficulty of providing excitation along the entire length of the waveguide cavities. For example, as shown in the patent to Laakmann, U.S. Pat. No. 4,169,251, a single waveguide cavity is formed between a pair of mutually spaced dielectric blocks, between which are interposed a pair of mutually spaced solid electrodes which extend laterally outwardly beyond the sides of the dielectric blocks. Construction, size and configuration of such an arrangement is limited by the necessity of providing such interposed electrodes. Moreover, the arrangement is not adapted to provide a compact, lightweight laser having multiple cavities.
Accordingly, it is an object of the present invention to provide a multiple cavity waveguide which avoids or minimizes problems mentioned above.